Posts Tagged ‘On Physics and Philosophy (book)’

The Beginning of the End
So this is it for me and Bernard d’Espagnat’s On Physics and Philosophy.

In the final chapter d’Espagnat allows himself to speculate on the philosophical and spiritual importance of his veiled reality (which he capitalizes) in particular, and the results of modern physics in general.

The chapter is entitled “The Ground of Things.”

It is in these concluding sections that d’Espagnat makes his final defence of a materia prima, a mind-independent reality, before the objections of both realists (who concentrate on empirical reality) and antirealists (who say mind is all).

Some of those arguments say there’s no reality-in-itself, some say it exists but is inaccessible, and others say empirical reality is “reality.”

Kant vs d’Espagnat
D’Espagnat believes “the Real” is a mystery as it is (in his opinion) not accessible through discursive knowledge.

He notes Immanuel Kant distinguished between phenomena and “reality-in-itself,” but disagrees with Kant that a mind-independent reality is just a boring “limiting concept” filled with “pure x.”

Cassirer vs d’Espagnat
Ernest Cassirer strongly objected to being content with a “mystery,” which he felt would be an unbearable block to scientific inquiry.

D’Espagnat says when possible the search for clarity is admirable, but the true spirit of science is to follow where the facts lead it.

The quantum entanglement shown in “Aspect-like experiments” (by Alain Aspect and others) are just part of our evolving scientific knowledge.

Materialists vs Mystics
Sometimes one should approach “mystery” the way mystics, poets, or composers have done so (though more often in the past).

Realists (materialists) have no reason to believe they hold all the keys to knowledge, even in principle.

As for the antirealists (and instrumentalists), if they think reality is something we ourselves build up, then mystery can hardly be called an exceptional “illusion.”

Affect vs Effect
The “affective” element of human existence is an aspect that seems to circumvent our rationality.

Kant felt the “affective mind” was not “ordered on concepts” and therefore could shine no light on Being.

D’Espagnat is more sympathetic to Descartes. Thought leads to the self-evidence of existence (“I think, therefore I am”), but d’Espagnat says just as self-evident will be our “joys and pains.”

We base our conjectures on what we know most intimately, and what could be closer to us than our “affective consciousness”?

This too should be able to inform us of Being, perhaps in some circumstances even better than science can.

Realism vs “the Real”
We can take a very realist position and imagine that if mankind disappeared the stars would continue in their courses.

This is an argument for a mind-independent reality—just not the one d’Espagnat has in mind.

D’Espagnat says just because our present existence is usually most conveniently described in realist terms (such as conventional space and time) doesn’t mean the realist position is actually true.

Even particle physicists who use the realist language of minuscule points and well-defined trajectories know that’s not what’s “really” going on.

Radical Idealism vs “the Real”
On the other hand radical idealism believes there is no reality outside the mind.

In other words, there’s no mind-independent reality.

D’Espagnat says his earlier arguments, either based on no miracles or intersubjective agreement (see chapter five) undermine idealism but not his veiled reality position.

However, he felt this level of reality would still be situated within ordinary space and time.

It’s on that count that d’Espagnat rejects Heisenberg’s arguments as irrelevant as “the Real” is not located in space and time.

Pro vs Con
In the end Heisenberg finds arguments both for and against a “ground of things” dubious.

You can argue against a “ground of things” but only in the sense of a “pregiven,” describable “world-per-se.”

D’Espagnat finds the “pro” arguments based on “commonsense” or a pre-existing mathematical reality also unconvincing.

D’Espagnat believes a “more fact-based reasoning” is called for.

Universality vs Events
D’Espagnat says over the past half-century interest in chaos and complexity led some scientists to demote scientific laws and promote the role of the “event,” previously seen as more or less accidental.

He says he argued against rejecting the “universal” in a 1990 book.

He’s more ambivalent about the emphasis on “events,” which he says takes place within empirical reality.

That reflects the way we’re “apprehending the Real” but doesn’t meant that’s what “the Real” is all about.

For instance, we don’t see objects as nonseparable, but that’s what quantum theory tells us.

D’Espagnat says Edgar Morin and others in this school of thought have somewhat retreated from their emphasis on events, complexity, and disorder.

Morin acknowledges that “Aspect-type” experimental results have shown some limitations in his approach.

Structures vs Hints of Structures
D’Espagnat says “the Real” is prior to mind-matter splitting, so the mind may detect hints of the mind’s source, which is “the Real.”

That veiled reality is not the same as the underlying reality described by structural realism.

D’Espagnat says mind-independent reality is not the source of our physical laws. At best these laws are distortions of the “great structures” of “the Real.” At worst they’re just very obscure “traces.”

In the end “the Real” isn’t describable, indescribable, or party describable.

The first two options imply a total presence or lack of description, and the third option implies “the Real” has parts, which isn’t the case, says d’Espagnat.

Conceptualization vs Meaning
If “the Real” can’t be conceptualized can it have any “meaning”?

D’Espagnat cites Zwirn’s argument imagining a creature as far ahead of humans as humans are ahead of dogs or monkeys.

We can conceptualize things that dogs or monkeys can’t, so surely a superhuman being could conceptualize things we can’t.

D’Espagnat believes that poets can allude to things that we somehow know exists even if these concepts can’t be made explicit.

But d’Espagnat notes that new science has allowed us to move past old science’s viewpoints, such as materialism.

So thought has been able to illuminate some deep matters.

Platonism vs d’Espagnat
D’Espagnat sees similarities between his view of causality and Aristotle’s.

Aristotle was a realist and was concerned with causality not just in the realm of phenomena but in “reality-in-itself.”

Furthermore, Aristotle was not beholden to the idea that causes precede effects.

Instead there could be “final causes” to which things might tend under the influence of Aristotle’s God.

As d’Espagnat’s veiled reality is beyond time, “the Real” could impart such a “final cause” on empirical reality.

Also, Aristotle’s interest in causation beyond mere phenomena reminds d’Espagnat of his own interest in causation between “the Real” and empirical reality.

Aristotle distinguished between “power” and “act” while Newton supposedly saw just “act.”

Aristotle saw matter as the seat of a vague potentiality.

Materia prima is pure potentiality.

“Informed matter” exists on more and more complex levels. Simple beings can be the “matter” for more complex beings.

These complex beings in this process are more “real” as their potentiality is expressed.

Therefore the deep meaning of reality lies not in the tiny components of complex beings, but rather the meaning is the complex beings themselves.

In a similar fashion, in empirical reality the wave functions have an “epistemological reality” at a lower level than, say, macroscopic objects in the wake of decoherence.

Although Heisenberg did not cite decoherence he did ponder the possible role of wave functions as a “materia prima.” Abner Shimony went on exploring this issue.

However, they’ve both admitted it’s hard to formulate these ideas precisely.

Plato vs d’Espagnat
As for Plato, d’Espagnat reminds us of his earlier concerns about the Plato’s Cave.

However, for Plato the deeper meaning was not in the things themselves.

They didn’t reside just in “us” either. He wasn’t a radical idealist.

Platonic Ideas (and his concept of the “Good”) bear resemblance to “the Real.”

However, Platonic Ideas are conceptualizable while “the Real” is not.

Many scientists believe, still, that analyzing more and more sense data will get us closer to the deeper meaning of reality.

However, advances in science have relied on a “rapprochement” between science and a philosophical position (Platonism) that questions such a program.

D’Espagnat notes that “Platonism” is a term nowadays often interpreted as “Pythagorism” with real mathematical objects.

D’Espagnat does not agree with “Pythagorism,” but notes that there’s some relationship between it and Platonism.

Even veiled reality has a smidgeon of Pythagorism in it as empirical reality’s objects are somehow a dim reflection of “the Real.”

Einstein vs d’Espagnat
Albert Einstein appears to have believed “the Real” could in principle be apprehended in its details, even if in practice that was rarely possible.

However, the goal remained to explore this deeper world by discovering universal laws.

Einstein also believed in three levels of religious experience.

The first was based on fear, the second morals, and the third transcends ordinary human views of God.

At this third level, Einstein thought, a sublime order is reflected in nature and in thought.

Even scientific materialists no longer believe the common materialism that the mass media disseminates.

However, there have also been developments that make us question some of Einstein’s philosophical positions.

D’Espagnat sees some compatibility between his views and Einstein’s even if Pythagorism doesn’t have to be entirely correct.

“The Real” does not have to be totally intelligible.

The human mind may tend toward the structures and qualities of “the Real” in the sense that Max Planck had a strong affective experience in his theoretical work.

It’s not necessary that mathematics reveals everything about “the Real.”

Rather, as long as we have some concept of “the Real” that we can tend to, the structures and qualities of the mind may be drawn to it even as it never fully understands it due to the mind’s limitations.

The Spiritual vs the Scientific
Maybe this idea is closer to Einstein’s third-level religious experience rather than a completely knowable “Real.”

The human mind tends to quest and exploration, though never able to fully accomplish what it desires.

Einstein was still grounded in physical materialism.

Later developments in physics have shown us something more human-oriented. We can’t limit Being to just material components.

The mind may somehow “recall” aspects of Being as consciousness is not just a product of matter.

Archetypes of some of our feelings may lie with “the Real.” There’s no way to prove this, or disprove this.

But crucially we can no longer see science as an impediment to the “spiritual impetus that moves mankind,” an impetus, according to Einstein, that makes us desire to live “the whole of what is.”

Philosophers question the basis of our reality while consciousness researchers (such as neurologists) take physical realism as a given (whether they’re conscious of this or not).

Mind vs RealityRadical idealists, who think mind is “primeval,” may wonder about the relationship between mind and “basic reality.”

Supporters of d’Espagnat’s “veiled reality” or “open realism” approach are even more motivated to investigate.

Truth vs Reality A physical realist can say that a true statement is “adequate to what reality really is.”

This is the “similitude theory” of truth.

Reality vs Representations But if we don’t have access to reality as it “really is” then we might say we have access only to “human representations” of “the Real.”

Instead of worrying about whether statements are true to reality you might worry more about the verifiability of statements.

Knowable vs Unknowable Reality Another problem with the “similitude” approach is that quantum mechanics, the best model of the world we have, fundamentally deals with observational probabilities not plain and simple facts.

Even resorting to a Broglie-Bohm approach doesn’t help as “hidden variables” will be inaccessible to the observer even in principle.

A supporter of the veiled reality approach has to take a somewhat nuanced tact.

Very broad statements about physical constants or “existences prior to knowledge” may hint at “the Real” without claiming to say anything directly about “the Real” as it “really is.”

Appearances vs Veiled Reality If we’re not supposed to trust in “appearances” then what is reality really like?

We might think that “the Real” is just an updated version of “appearances.”

Or maybe mind-independent reality is so independent that it’s entirely inaccessible.

D’Espagnat says both approaches are too extreme.

Causal Links vs Predictive Laws We like our ordinary, everyday version of “realism” because it lets us imagine particular cause-and-effect relationships.

It’s easier to explain things when we can point to particular causes rather than just patterns of observational predictions.

D’Espagnat says some causal links are genuine and independent of us, but our interpretation of these links is very much our own.

For instance, causality is closely related in our minds to the notion of “will,” which entails a very anthropomorphic (human-centred) view of reality.

Intersubjective Agreement vs Appearances But what if a group of humans (and maybe even non-humans!) agree on certain observations?

D’Espagnat says that this agreement combined with rules of observational prediction mean this is our “reality.”

Saying they’re just “appearances” is misleading. It’s a kind of “reality.”

However, modern physics reminds us that humans tend to “reify” (think of the world as a set of objects).

So we still have to keep in mind that empirical reality is not the same as “the Real.”

Empirical Reality vs Mind-Independent Reality Although d’Espagnat is comfortable with the term “reality” to describe our empirical reality, he says we have to remember these are two “orders” or “levels” of reality.

Empirical reality isn’t just a mere variant on “the Real.”

Identity Theory vs Efflorescence Theory In some of the more nuanced sections of the chapter d’Espagnat makes a distinction between identity theory and efflorescence theory.

Identity theory states that a genuine sensation or awareness (perhaps even thought in general) is traceable to neurons or their components.

The material aspect of these neurons is the ultimate cause of our sensations.

Efflorescence theory attributes sensations and awareness to “neuronal activity” rather than the material aspects of neurons or their components.

Strong vs Weak Completeness D’Espagnat’s main line of attack against identity theory is the completeness principle.

In its strong version, quantum mechanics is assumed to be able to describe anything at all.

In its weak version, if any theory can describe something then quantum mechanics can do so as well. This leaves open the concept of hidden variables.

Since quantum mechanics is antirealist it’s hard to imagine how the strong completeness principle is compatible with identity theory.

Even if you take the weak version of the completeness principle all you can conclude is that the identity theory may be true—but we can never show it to be so.

But what if you reject the completeness principle entirely?

If you used the Broglie-Bohm model you’d still have to deal with an entangled wave function, so sensations can’t be attributed just to some limited coordinates of a particular neuron.

Or you can take the Roger Penrose approach by adding nonlinear terms to the Schrödinger equation.

D’Espagnat says that approach may work, but he finds it too ad hoc. It’s also work still at an early stage, yet to face the scrutiny a full theory would need to endure.

But neurologists believe brain states not neuronal states are what drives awareness. You can’t pinpoint a particular neuron or group of neurons that are responsible.

It’s the collective action spread across the brain that is associated with awareness.

D’Espagnat notes the parallel to quantum entanglement.

Protomentality vs Mentality Alfred North Whitehead and other thinkers in the past have wondered if simple organisms or even inorganic entities can have awareness?

Abner Shimony’s “potentiality” might satisfy some objections to this concept of protomentality.

Various entities have the potentiality of consciousness, but this potentiality isn’t actualized unless a nervous system is present.

Consciousness vs Components of Consciousness As a final objection to the efflorescence theory, d’Espagnat says that any component we cite will be part of our empirical reality.

Empirical reality depends on our consciousness.

Therefore how can something that depends on our consciousness be the cause of our consciousness?

D’Espagnat vs The “Received” View The “received” view that thought is produced by matter is, according to d’Espagnat, “slightly useful” as a model but must be rejected as a plausible philosophical stance.

Relative Quantum States vs Relative Consciousness Because the observer decides what to measure and how, quantum states are “relative” to these procedures.

However, some quantum rules may be considered “in isolation.” They’re not predictive observational rules and hence don’t involve probability.

They’re more like descriptions.

However, to understand the quantum world you have to consider all quantum rules not just pick and choose the non-probabilistic ones.

D’Espagnat says states of consciousness are somewhat similar.

Definite vs Indefinite States of ConsciousnessImagine a sealed-off laboratory. Paul makes a measurement. His state of consciousness is definite but Peter doesn’t know that until Paul, say, phones him with the measurement.

This is a version of Wigner’s friend, and can be extended over and over again, with an observer outside a sealed room, which contains an observer outside a sealed room, etc.

Peter thinks Paul’s state of consciousness is not just unknown (before the phone call) but also undefined. It’s a superposition of possible results (pointer values, for instance).

Yet once Paul makes the measurement, Paul’s state of consciousness is definite from Paul’s point of view.

Consciousness vs The Absolute This apparent conflict doesn’t change the fact that physics is all about predicting observations, says d’Espagnat.

However, there’s a related issue.

We shouldn’t think that “predictive states of consciousness” are like some Absolute or can even be a substitute for the Absolute.

Quantum states are relative, and so are states of consciousness.

More precisely, states of consciousness that are predictive are relative.

Physical vs Mental So we see some sort of “solidarity” between the physical and the mental, but that doesn’t mean the mental can be reduced to the physical.

Wigner’s Friends vs Ultimate Reality The series of “Wigner’s friends” who occupy increasingly large rooms is suggestive of an ultimate reality that we cannot gain access to. Wigner’s friends don’t have access to the overall wave function.

Predictive vs Non-Predictive Consciousness However, nothing prevents us from pondering non-predictive states of consciousness.

When Paul makes the observation, his state of consciousness becomes well-defined. It’s no longer predictive.

Veiled Reality vs Co-Emergence Michel Bitbol, Hervé Zwirn, and other authors speak of thought and empirical reality “co-emerging” at the same time.

It’s a “self-qualifying” process by which structure emerges from an initial and total lack of structure.

D’Espagnat says his veiled reality viewpoint has an “ultimate ground” endowed with general structures even if they are “far from being knowable.”

This ultimate ground may form the basis for not just scientific laws but also creative and mystical endeavours.

A description of rainbows might illuminate how we speak about quantum systems.

A rainbow (including its two “bases”) will look different from different locations.

Hence, the particular rainbow someone sees is observer-dependent.

The same reliance on location is true if you set up automatic cameras.

Hence you can’t say that just because we’ve taken a picture of a rainbow that this rainbow “really” existed before that observation.

Similarly, out tendency to “reify” (seeing something as concrete and real) means we jump from an observation to assuming what was observed somehow pre-existed.

If we can argue that a rainbow doesn’t pre-exist, we should be able to argue that a quantum object doesn’t pre-exist either.

Dinosaurs vs Humans
However, surely dinosaurs existed before humans ever walked the earth. No observation was required to bring them into existence.

D’Espagnat says that dinosaur bones are like the pointers of an experimental set-up. We see something and conclude it’s real.

Though d’Espagnat says it’s real, he specifies it’s real in the realm of “empirical reality.”

However, this empirical reality is hardly an arbitrary production. Its qualities are severely constrained, and in the end observers tend to see mostly the same thing.

Explanations vs The Final Key
Classical physics can still provide us with “explanations” as long as we don’t presume they derive from a deeper reality.

D’Espagnat adds that we should not conclude that these explanations are the “final, ultimate key” to understanding the world.

D’Espagnat vs Other Views
I’ve concentrated above on d’Espagnat’s ultimate positions, but here are some examples of how he explains his disagreement with other people’s positions (real or conjectured).

D’Espagnat vs Cassirer
If you see correlations in a quantum experiment then d’Espagnat has trouble imagining Cassirer’s “logical necessity” could explain each particular observation in a sequence.

True, Cassirer could choose (or could have chosen, as he’s now dead) hidden variables, but d’Espagnat says that’s too “metaphysical” for Cassirer, and the Aspect-type experiments have refuted them anyway.

D’Espagnat says that whole idea is something the neo-Kantians were trying to get away from, so again it doesn’t sound like Cassirer.

Nonetheless, d’Espagnat says his own position is consistent with considering the “Real” (with a capital R) to consist of such a logos.

D’Espagnat vs Carnap
Carnap says scientists should be more modest. They shouldn’t try to explain the “why” but just the “how” of phenomena.

Carnap’s position is that simply producing entities, such as Driesch’s “entelechy” as an explanation for tissue regeneration, is irrelevant as there are no “laws” connecting conditions and observations.

So what about d’Espagnat’s “Real”? Is it just a meaningless entity?

It doesn’t help us predict anything, so maybe it’s not an explanation at all.

D’Espagnat responds by saying scientists long ago were implicitly believing in the realism of a world ruled by classical physics even if explicitly they concerned themselves with just the laws of observation.

Even some realists nowadays, says d’Espagnat, acknowledge that there could be an underlying reality, not attainable through “discursive knowledge,” that nonetheless grounds our empirical reality.

Furthermore, if laws relate just to our known observations, then what happened before we made those observations?

Carnap, according to d’Espagnat, said laws could exist before such observations but the truth of the laws could not be judged.

D’Espagnat says this amounts to Carnap’s acknowledging a “human-independent reality” that has a structure we might never know.

Since quantum mechanics only predicts observations and does not “explain” underlying reasons, this implies to d’Espagnat that a “Veiled Reality” has a meaning even if we can’t explore it empirically.

But what if we imagine Carnap meant some kind of “linguistic framework” involving “nature” and “existence” that replaced the usual meaning of those terms?

In a world ruled by classical physics it makes sense to speak of “things” and their qualities makes sense.

In a world ruled by quantum physics it makes sense to speak of “sense-data” rather than “things.”

D’Espagnat says this approach works fine for making sure scientific statements are clear.

But it’s not satisfactory from the philosophical point of view.

Carnap, d’Espagnat says, is just “masking” not “eliminating” the connection we make between an explanation of observations and an explanation of what’s going on in some underlying reality.

Since a linguistic framework is “chosen by us” according to Carnap it sounds a bit arbitrary and not like a genuine explanation.

Just Causes and Side Effects
Chapter 14 (“Causality and Observational Predictability”) of Bernard d’Espagnat’s On Physics and Philosophy examines how, and if, we can use the concepts of causation and influence to explain the world.

Reality vs Observations
Taking a break from examining the “notion of reality” d’Espagnat uses this chapter to argue it’s better to predict observations than predict “things as they are.”

Animism vs Empiricism
Aristotle saw causation as related to human will, and even inanimate objects seemed to have some animistic will—as seen when a falling stone somehow desires to return to its natural resting place.

Empiricists went to the other extreme. Physical laws should just be descriptions of events and their regularities. However, what initial conditions are the “cause”? You end up with too many empirical laws.

Mathematical vs Physical Determinism
If two very close points rapidly diverge then they’re not likely to be “physically deterministic.” It’s too hard to calculate their exact paths.

“Strong objectivists” argue that science accumulates knowledge about an underlying reality, not just our experimental observations.

Some strong objectivists argue that “chaotic” behaviour is an example of indeterminism, and others argue initial conditions have to be repeated exactly for us to say deterministic laws apply.

The first approach implies imperfect observations or calculations show reality is indeterministic, but that’s strange since strong objectivists believe in an underlying reality separate from our fuzzy data.

The second approach is a problem since a strong objectivist can’t be absolutely sure the initial conditions won’t be repeated.

Laws vs Predictions
D’Espagnat also criticizes the claim we’ve seen the “end of certainties” just because some calculations make predictions impossible.

He says that’s too harsh as we can still believe in our laws even if sometimes in practice we can make reliable predictions only for the near future.

Classical physics falters where quantum physics and its apparent indeterminacy excel, particularly on the microscopic level.

Yet d’Espagnat says the defining feature of quantum mechanics is not its indeterminacy but its “weak objectivity.” The theory confines itself to observations of reality, not claims about reality itself.

Individual vs Statistical Determinacy
D’Espagnat agrees with Kant that “regularity in time”—in which one kind of event is followed consistently by another—is a good way to distinguish the empirically real from, say, the events of a dream.

Kant’s “sin of omission” (understandable because of his time and place) was not to consider statistical regularities in which ensemble probabilities are deterministic.

D’Espagnat emphasizes that quantum mechanics makes reliable predictions for observing ensembles of quantum systems, but these are not probabilities of ignorance about individual systems.

At first glance quantum mechanics may seem indeterministic, but if you keep in mind quantum predictions are about observations of multiple systems then it too is deterministic—if only “statistically.”

Laws vs Facts
D’Espagnat warns against “a variant of nihilism” if you don’t pay enough attention to the difference between laws and facts.

He says even Dirac’s musings that universal constants (such as the speed of light) might change over time don’t threaten that distinction.

The nihilistic danger, d’Espagnat says, comes from sociologists, epistemologists, or “pure philosophers” who see in the history of a changing universe a fundamental lack of stability.

They fail to distinguish between laws and facts, or they fail to appreciate the significance of the distinction.

Causes vs Influences
D’Espagnat imagines a Laplace daemon that can possess total knowledge of events in part of the universe.

The fixed speed of light means, in an Einsteinian world, the daemon need only check events in a point’s past light-cone to predict that point’s future.

However, Bell’s Theorem combined with the experiments of Alain Aspect (and others) proved that the locality hypothesis is false.

Add to that the order (in time) of events can vary by reference frame, and we see that (earlier) cause and (later) effect can be ambiguous.

Physics vs Philosophy
In the second half of his book On Physics and Philosophy Bernard d’Espagnat explores more of the philosophy and less of the physics of quantum theory, and I’m taking notes to keep track of where he’s headed.

In chapter 13 (“Suggestions from Kantism”) d’Espagnat says that physicists nowadays aren’t entirely sure how their scientific theories and results are to be interpreted.

Kant did not reject the idea of an underlying reality, otherwise he would have discarded the “thing-in-itself” concept.

Kant did, however, say that Pure Reason would not be able to make any pronouncements on it. Beliefs and speculations are fine as long as we don’t call them scientific or rational views, he said.

The Table vs the Representations of the Table
Here is a basic problem: if you look at a table you not only have a representation of that table somehow inside of you, but you also believe there’s a table somewhere out there.

Can we check that this representation is accurate? Well, we can’t check what’s “really” out there since our senses give us just a representation of the table.

Space vs Experience
Kant argued that the very concept of space and spatiality was “a priori.” We’re more or less born with it as we need to peg various bits of sense data somehow in relation to each other.

D’Espagnat disagrees, saying the same argument could be made about riding a bicycle or learning to swim. He says Kant, living in a time ignorant of the evolution of species, would also not have considered “learning by apprenticeship.”

D’Espagnat finds himself not just rejecting the realists who argue for the “absoluteness” of space and time, but also the idealists who claim Kant pinned down the foundations of the argument.

Not just evolution but also quantum physics was lacking in Kant’s approach, yet even today philosophers consider a “demonstrated truth” the view that spatiality is just the mind’s way of framing phenomena.

Modern physics shows that concepts of Euclidean space, universal time, and precise localization are misleading, even if we need those concepts to operate as humans in our ordinary macroscopic lives.

Kant’s vs Quantum Theory’s Objective Language
In any event, Kant sees science as addressing phenomena, so his version of science is “weakly objective.” So is quantum physics, which speaks of experimental setups and predictions of experimental observations.

But Kant uses the language of objective reality with little modification, while quantum physics uses terms such as electrons and virtual particles for reasons of reluctant convenience.

Kant vs his Followers
Kant’s followers became much more hostile to the idea of an objective reality. Kant talked about the “thing-in-itself,” even if inaccessible to science directly. But neo-Kantians rejected the notion except as a “limiting concept.”

D’Espagnat looks at Ernst Cassirer, a neo-Kantian writing around a century ago. D’Espagnat says he may be the “clearest” of all the neo-Kantians.

Cassirer’s Concept of Concepts vs Traditional Concepts
Cassirer was very interested in the process of coming up with concepts.

He noted that traditionally a big concept contains little information because so many distinctions get blurred.

For instance, we can move from an oak to a tree to a plant to a living being, a concept so broad we hardly have words to describe it.

But with mathematics the bigger categories combine all the qualities of the smaller categories that feed into it.

For instance, the concept of second-degree curves doesn’t mean we can’t tell a circle from an ellipse any more. We just have to plug the right values into the right parameters and we can get a circle.

Logical Necessity vs Quantum Results
Cassirer tries to describe science as a mathematical approach incorporating more and more concepts through some sort of logical necessity.

Reason and the universal scope of logical necessity form the basis for some sort of Being.

But d’Espagnat says that’s just an analogy. If we look directly at quantum physics we see it doesn’t link disparate impressions into some sort of logically and causally required arrangement of entities.

Cassirer’s views on the rules of knowledge and logical necessity put great emphasis on our mental powers to create order rather than some reality “out there.”

Yet d’Espagnat reminds us that experiments often refute one theory or other, so there is something “out there” that can derail some view and just say “no.”

Complete vs Ongoing Pursuit of Knowledge
Furthermore, d’Espagnat’s concept of a “veiled reality” won’t leave us exasperated and depressed, he says, because we will always be able to come up with better and better ways to deal to generalize about phenomena.

Mind-independent Reality vs Internal Consistency
D’Espagnat says some modern philosophers with “Kantian or empiricist inclinations” are less resistant to the idea of an independent reality than Cassirer was.

D’Espagnat says that Hilary Putnam’s “internal realism” sees descriptions evaluated by some kind of “ideal coherence” that keeps our beliefs consistent with each other and with experiences represented in those belief systems.

But d’Espagnat says Abner Shimony thinks Putnam gives up too easily in rejecting any kind of correspondence between our senses and a “mind-independent or discourse-independent ‘state of affairs.'”

Shimony and d’Espagnat think the concept of a “protomentality” has some similarity with quantum mechanical concepts.

Bas van Fraasen came up with a “constructive empiricism” that rejected scientific realism. He said it might be useful to consider structures and processes not directly accessible to an observer, but they’ll have no intrinsic reality.

On the other hand, Fraasen said the issue of what is observable and what isn’t should be left to science not philosophy: the “Grand Reversal.”

Empiricism vs a Knowing Subject
But can Fraasen stay an empiricist when he’s making use of a “knowing subject”?

Shimony thinks empiricism needs to be dropped for some kind of realism — with a strong mental component.

In the end d’Espagnat agrees with Shimony that there must be some way to “close the circle” even if there is a “dark cloud” making the project difficult.

That dark cloud is the impossibility of considering quantum states to have an ontological status.

D’Espagnat says that as long as contemporary philosophers stick to philosophy they have trouble radically casting doubt on veiled reality, or even realism in general.

Only when modern physics is considered do we see how impossible it is to be a conventional realist.

Material Witness
In chapter twelve of his On Physics and Philosophy Bernard d’Espagnat tackles three kinds of materialism: dialectical materialism (briefly), “scientific” materialism, and what he calls “neomaterialism.”

Ultimately… ultimate reality isn’t the same as “empirical” or “epistemological” reality, something materialists just don’t get.

At least that’s what he says, and I largely agree.

Here’s my summary of the chapter.

Dialectical Materialism vs Bohr
D’Espagnat says he’s not going to do a detailed analysis of dialectical materialism. He says it’s been sufficiently dismantled elsewhere. However, he warns against seeing too many parallels between Neils Bohr’s approach and this form of materialism.

Bohr’s thought and dialectics may share some general features, but that’s different from dialectical materialism. Bohr had a “human-centred” approach, which could be called materialism only if you radically changed the meaning of the word.

Scientific Materialism vs Atomism
D’Espagnat says “materialism” or “mechanism” doesn’t automatically refer to atomism. Descartes didn’t believe in atoms, and even in the 19th century ether and fields lay outside the realm of the atom.

Macroman on the Street vs the Microworld
The man on the street and even many scientists (particularly in the softer sciences such as biology) think of nature as composed of smaller and smaller grains or specks, eventually leading to atoms. This microworld has (roughly) the same nature as the macroscopic world we experience.

The problem with that idea is that standard quantum theory and the experimental results used to test it show conclusively that atoms, particles, and the forces emanating from them just aren’t like the world at large (as we experience it). This material reductionism doesn’t work.

Standard vs Non-standard Interpretations
Penrose (calling himself a physicalist) adds gravitational effects to the Schrödinger equation. Sokal and Bricmont rely on Broglie–Bohm. However, the first choice is more a research program than a fully fledged theory, and the second choice runs into some trouble with relativity.

The Sokal and Bricmont approach combines corpuscles with nonlocal entities or forces that have the same strength whatever the distance. This isn’t your grandmother’s materialism.

Empirical Reality vs Materialist Reality
Standard quantum mechanics rejects both approaches. At best these materialist approaches describe some “empirical” or “epistemological” reality, a product of how our “mind structure” divides and categorizes reality.

Positivism vs Materialism
Some materialist apologists say quantum mechanics is a product of its times: the 1920s, when positivism (and its emphasis on observation rather than underlying reality) reigned.

D’Espagnat rejects that objection. He says that whatever the origins of quantum theory, rival interpretations still need to be bolstered by evidence.

Research vs Traditions of Research
Michel Bibol and Larry Laudan offer subtler challenges by examining the higher-level assumptions that scientists use. Laudan calls them “traditions of research,” which Bitbol calls “values.” They’re what imparts meaning to a scientific quest.

Observations vs “Ampliative” Arguments
D’Espagnat acknowledges that when mainstream physicists reject Broglie–Bohm because its concepts are unnecessarily complicated or because “action at a distance” messes with relativity they are using “ampliative” arguments.

These are arguments that go beyond what the observations are telling us. After all, physicists could reject the relativity principle as long as they come up with some theory that uses other principles, but acts as if the relativity principle still works.

Bohm vs Materialism
However, even David Bohm rejected materialism. He first spoke of a wave function then later a quantum potential. Neither is localized, hardly what a conventional materialist would call real.

Although Bohm found a way to explain physics without specifying consciousness, he also noted that quantum physics suggests a “mental pole” exists.

Neomaterialism vs Matter
A third approach to materialism comes from André Comte-Sponville.

He acknowledges nonseparability, a concept that other materialists ignore. D’Espagnat calls this approach “neomaterialism.”

Comte-Sponville gets himself into definitional circles trying to define “matter.” It’s supposed to be everything (but a vacuum), yet also produces the mind. However, if thoughts are real then they’d already be part of “matter.”

Neutral vs Suggestive Terms
D’Espagnat also criticizes Comte-Sponville for using “image-carrying words” such as “matter.” D’Espagnat notes that he himself doesn’t use “matter,” “God,” or “spirit.” Rather he tries to use neutral terms such as “mind-independent reality.”

Nonseparability vs Neomaterialism
Comte-Sponville says the primary question is whether matter is idealist or spiritualist on the one side, or of a physical nature similar to what we experience on the macroscopic level. He’s not an idealist or spiritualist, so he clearly believes in a physical reality.

But as with scientific materialism the idea that reality bears any resemblance to our macroscopic experiences is blown out of the water by quantum physics.

Nonseparability—which Comte-Sponville says is a “mystery”—is an issue whatever theory you choose. It ensures that “ultimate reality” is nothing like our everyday experiences.

Utility vs Evidence
Comte-Sponville eventually acknowledges that if matter includes thought then matter can’t be defined as everything except thought.

However, he says that ultimately what the “natural sciences” say is less important than neomaterialism’s purpose: to explain mind from concepts other than mind, and to do all this to “defeat religion, superstition and illusion.”

D’Espagnat says this argument about the usefulness of neomaterialism just ends up being a circular argument. Deeply held convictions are not themselves an argument.

Empirical vs Ultimate Reality
Ontologically interpretable theories are not consistent with experiment. D’Espagnat says particles and their attributes have a well-defined existence only in relation to knowledge, hence the mind.

Our knowledge of particles and other micro-objects are just that: a kind of knowledge, hence pointing to elements of an empirical, not ultimate, reality.

D’Espagnat says that he and Comte-Sponville both agree that “existence” comes before “knowledge.” But d’Espagnat says mind comes from an “independent reality” not “empirical reality.”

These traditions use values that neither explain nor predict. They are not testable.

These research traditions may include contradictory theories under their umbrella. But some scientists attach a lot of meaning to this identity, and aren’t likely to give up on the term “materialism.”

On a day-to-day basis physicists are using and abusing terms from classical physics such as “particles.” Since physicists would find it hard to move ahead just pondering observations and equations, these concepts are convenient components of a “fabricated ontology.”

D’Espagnat warns these scientists that relying on this ontology to support their rationality may be useful from a practical point of view. Just don’t convert that choice into “an illegitimate doctrinal creed.”

Philosopher’s Walk
A little past the halfway point in Bernard d’Espagnat’s On Physics and Philosophy he switches from a look at the relevance of physics to philosophy to the relevance of philosophy to physics.

If the first chapter of part two, chapter eleven, is any indication, the last half of the book should be a much easier read than the first, though perhaps less satisfying.

It was a huge challenge to wade through d’Espagnat’s descriptions of quantum theory and interpretation, hence I felt the need to write (and post) lots of notes to help me out. At least I felt a sense of reward whenever I finally grasped something of the physics.

But as far as I can tell I agree with d’Espgant’s philosophy anyway. Part two may make easier reading, but I already felt a lot of the modern philosophy, soft sciences, and cultural studies he critiques was just plain hokum. I don’t need more convincing.

In any event, I will trudge on, and I expect I’ll be posting updates to my dualistic summary much more often now.

Science vs Philosophy
Descartes, Pascal, and Leibniz were brilliant scientists and philosophers, but by the eighteenth century a huge breach developed.

Intuitive vs Unintuitive Notions
Specialization works when concepts such as (in Fourier’s time) “hotter” and “colder” seem obvious, so don’t need to be defined by a theory.

But what’s a quantum field or space-time metrics? Then we do need to consider the nature of such concepts.

Ontology vs Operationalism
The physicist can give up his exclusive interest in behaviours, or can decide that “behaviour” is just a series of recorded observations.

The first option sounds like philosophy, while the second gets close to operationalism.

Physics-Aware Philosophy vs Philosophy-Aware Physics
In first part of his book d’Espagnat called on philosophers to pay attention to the physics. In this second part he calls on physicists to pay attention to the philosophy.

Quantum States of Confusion
The weeks or months between entries do not reflect a lack of desire to post, or to read, or to learn. I’ve just found Bernard d’Espagnat’s On Physics and Philosophy a tough slog.

His rather involved prose and the often bewildering translation combine to produce some very indecipherable moments, and my merely rudimentary understanding of quantum theory doesn’t help much either.

Here’s the latest of my chapter summaries, presented in the black-and-white dichotomous style that seems to match my thinking. Things are looking up, though, as he’s now getting into more philosophical territory.

Up to now he’s spent a lot of time justifying his interpretations by reviewing the experimental evidence and pointing out flaws in other approaches to the physics. It’s all perfectly legitimate, but as a lay reader I don’t always feel competent to judge who’s right.

So here’s a look at chapter ten of Bernard d’Espagnat’s On Physics and Philosophy.

Laws of Classical Physics vs Quantum Physics
D’Espagnat says that the laws of classical physics were “objectively interpretable” while in quantum physics the laws merely predict observations and the mutual agreement of observers.

Prediction vs Justification
D’Espagnat says modern physics prefers to come up with laws to explain patterns of observation rather than explain what’s “objectively” going on. Even so, can we justify why we choose these rules and why they work?

Quantum Laws vs Macroscopic Predictions
Quantum laws lead to paradoxes such as the Schrödinger cat, not observed in real life. Can we justify the laws behind these paradoxes?

Quantum Laws vs The Alternatives
But more generally, how do we justify (as in “explain”) that these laws work better than any others we might invent?

Decoherence theory shows how observing a whole ensemble of cats will show each one is either dead or alive in the proportions quantum mechanics predicts. Quantum laws are thus reconciled with observation—except that we generally observe individual cats not ensembles of them.

Mere Predictions vs Hidden Variables
If quantum mechanics merely predicts observations rather than says anything about the “reality” behind what we see then simultaneous states are just a way of calculating probabilities.

On the other hand, Broglie-Bohm’s pilot wave (see chapter two) has a particular probability of being in one of two regions—really being in one of two regions (equivalent to aA or bB).

Standard quantum mechanics says whatever the “Real” happens to be is what produces results that match quantum predictions. The pilot wave approach gets more ontological and suggests what the “Real” must look like to produce those observations.

The two approaches are compatible, though that doesn’t solve various problems with the hidden variable approach (as d’Espagnat has already pointed out).

He ponders conscious beings that can make predictions about themselves—making observations from within.

Consciousness vs Matter
D’Espagnat says both scientists and “the enlightened general public” look upon states of consciousness as states of matter.

Matter vs Sense Data
D’Espagnat says equating consciousness and matter is hasty, as the argument depends not on the concept of matter but rather on the concept of awareness, as in “registering sense data.”

Sense Data vs Reality
D’Espagnat says Berkeley, Kant, and the neo-Kantians followed the “great principle” that things take place “as if” our senses and classical physics give a true picture of reality.

In other words, the belief was that our sense data give us “an access to ontology.” However, quantum mechanics makes it clear that this principle is a faulty assumption.

The Schrödinger wave function just gives the probability that the (unorthodox) pilot wave is in some region of the system. No contradiction.

But in orthodox quantum theory the quantum state of the bacterium is an improper mixture of various states, so we get an apparent contradiction.

Microscopic vs Macroscopic Subjects
Bacteria are microscopic but humans are macroscopic. Decoherence theory kicks in, so in practice we can consider electron-human systems to be a proper mixture of two reduced wave functions. Therefore in practice their state of consciousness has predictive power.

Predictive Consciousness vs Predictive Science
D’Espagnat says he’ll explore notions of consciousness in chapter 18, but says the “scientific” definition of consciousness is limited to one of predictive power, and that’s because science itself limits itself to predictive power.

Predictive vs Non-predictive Consciousness
The bacterium or Schrödinger’s cat who thinks it’s alive cannot influence the outside observer if this state of consciousness is non-predictive, says d’Espagnat.

If you could somehow ask the bacteria what their state had been you’d find the results were the same as for a proper mixture.

But we’d assumed the quantum ensemble was initially a pure case (in other words, in an improper mixture).

Asking a question is like taking a measurement. It disturbs the system. Hence no contradiction.

Group vs Individual Observations
D’Espagnat says the generalized Born rule is “impersonal.” It makes predictions about the correlations among observers not what a particular individual observer will see.

But if the Born rule is applied to individual observers this correlation would be cut.

D’Espagnat is not comfortable with the “quite inordinate strangeness” that private states of consciousness would differ in this situation, and hence be deprived of some of their predictive power.

He does not, however, rule out this possibility.

Individual vs Group Observations
Although in theory the overall wave function must be the basis for predictions, in practice decoherence lets macroscopic observers rely on their own states of consciousness to make predictions.

Can this reliability of individual predictions be extended to group predictions?

Two friends are looking at the same pointer. By the conventional Born rule they will get the same “impression” of the pointer and hence build up the same kind of wave function to make future predictions.

The different waves that correspond to different impressions of the pointer mostly don’t overlap. That fact and decoherence assure us that the two friends’ predictions will coincide too.

Physics vs Philosophy
D’Espagnat notes a “turning point” in the book. He feels he’s shown the amazing predictive powers of quantum mechanics and its universality. Now he wants to explain why these rules work and where they came from. This takes him further into philosophical territory.

Instrumentalists vs the Kantians
D’Espagnat says the “diehard instrumentalists” think such questions are meaningless, while those sympathetic to a Kantian viewpoint think some explanations are in order but would be found “within the human realm.”

Naive Realism vs Open Realism
D’Espagnat looks for an explanation he calls “open realism.” He believes an explanation can acknowledge “what truly exists” without descending into a simplistic “naive realism.”

Scientists vs Philosophers
D’Espagnat says most scientists point to the obvious, common-sense appeal of some kind of objective reality.

Philosophers who lean to Kantianism or radical idealism feel there are no “objects-per-se.” We build up a representation of the world using our senses and intellect.

Most scientists say our body of knowledge has increased immensely since Kant’s time, which they say makes obsolete his reasons for doubting human knowledge as a reliable account of what’s out there.

Most philosophers would say Kant wasn’t daring enough. They say he should have rejected the very idea of a “reality-per-se.”

Kant vs d’Espagnat
D’Espagnat agrees that Kant’s arguments were faulty, though justified at the time considering he knew nothing of evolution or mathematical physics.

However, updated arguments lead to a conclusion roughly similar: science doesn’t seek knowledge of “the Real” but rather just of phenomena.

This is not a rejection of some human-independent reality. In this d’Espagnat agrees with Plato and Kant.

Empirical vs Objective Reality
D’Espagnat does not believe physics describes an objective reality. Rather, it describes at most some kind of “empirical reality.”

He is, though, impressed by the consistent nature of Maxwell’s equations and other major laws, leading him to think physics provides “some not altogether misleading glimpses” of the underlying structure of reality.

“The Real” vs Phenomena
D’Espagnat puts out there the idea of an “extended causality” in which “the Real” imparts some kind of non-quantitative influence on phenomena. He adds that this is just a supposition of his.

D’Espagnat vs Mohrhoff
Another approach comes from Ulrich Mohrhoff. He thinks some aspects of phenomenal space may be considered strongly objective as long as other aspects are discarded. He suggests that physical space does not intrinsically exist independent of the objects that are in them.

D’Espagnat vs Modern Philosophers
Compared to his disagreement with science’s “physical realists,” d’Espagnat says there’s a “high degree of convergence” between his views and many philosophers.

There’s still some difference of opinion. D’Espagnat believes in a veiled reality while many philosophers think reality is “radically unreachable.”

He also notes that many philosophers feel his “open realism” postulate is arbitrary. D’Espagnat admits it’s unprovable (he does call it a postulate, after all) but feels there are serious arguments to support it.

Existence vs Knowledge
D’Espagnat’s first argument for his postulate is that “existence” comes before “knowledge.”

He admits that the existence of a particular something may logically depend on the possibility of our knowing it.

However, he agrees with Plato and Kant that the very notion of existence can’t depend on our possible knowledge of this existence.

Beautiful Theories vs Falsifiability
D’Espagnat’s second argument for his postulate is that beautiful, consistent theories can be struck down by experiment. Theories predict consequences that can be contradicted by observations.

We can’t be totally in control of what we perceive or not. In d’Espagnat’s words: Something says “no.”

Realism of the Accidents vs External Influence
D’Espagnat’s third argument for his postulate refers back to chapter five’s “no-miracle” and “intersubjective agreement” arguments.

He says they do not support realism of the accidents or anything close to it. However, they do show, in his opinion, that physical laws depend at least partly on something that is not “us.”

Present vs Past Building Blocks of Knowledge
D’Espagnat’s fourth argument for his postulate is that a priori concepts of human knowledge change over time. Kant could rely on Euclidean space, universal time, and determinism to reject reality-per-se as the source of such concepts.

Nowadays science’s building blocks include curved space, space-time, and indeterminism. It’s hard to believe that we can rely on these basic concepts of human knowledge when they keep changing.

Also, Kant’s building blocks were very intuitive. Physics today uses unintuitive concepts that are so unintuitive it’s hard to believe they sprung from some innate concepts we hold.

So we’re left with either physical realism or contenting ourselves with science as prediction.

Physical realism has (in d’Espagnat’s view) been thoroughly demolished, leaving just the empirical/predictive option—with the caveat that there’s something out there that prevents us from being entirely arbitrary in our perception of reality.

Partial Knowledge vs Veiled Reality
D’Espagnat also mentions some misunderstandings he feels others have of his work.

He says Roland Omnès takes his concept of veiled reality and calls it some kind of “weak realism” in which only partial knowledge of reality is possible.

D’Espagnat says he never uses the term “weak realism,” and thinks Omnès doesn’t appreciate the huge jump from “independent reality” to “empirical reality.”

Veiled reality is no more partially knowable than Kant’s phenomena “are knowable bits of noumena.”

D’Espagnat repeats, though, that the mathematics of some physical laws may “vaguely resemble” some of the “great structures of ‘the Real.’”

D’Espagnat vs Esotericism
Although d’Espagnat says he’s mostly disappointed with the “esoteric visions” that have pointed to his writings, although there are some “intermediate cases.”

D’Espagnat appreciates Thierry Magnin’s approach to “levels of reality” but feels he got it wrong when he sees veiled reality related to “unpredictability and chaos,” the “constructive role” of time, and science as a social construct.

D’Espagnat does note that he’ll explore the objectivity of science in the next chapter, but his concept of veiled reality does not spring from that issue.

Veiled Reality vs Anomalous Phenomena
D’Espagnat says it’s understandable that the views of anyone not agreeing with a “mechanistic conception of nature” would be used to explain various “phenomena seemingly defying the laws of science.”

However, d’Espagnat believes nonlocality in no way explains supposed influences at a distance.

Neither does d’Espagnat doubt the “robustness of the physical laws,” but rather believes them likely to be “correct and universal.”

Finally, the concept of veiled reality addresses a philosophical understanding of reality, not the particulars of observed phenomena.